Device for sealing a drill hole and for discharging drillings or stripped extraction material

ABSTRACT

In a device for sealing a bore hole and discharging drill cuttings and stripped excavation material, including a housing adapted to receive sealing elements and an opening capable of being connected to the bore hole, one side wall of the housing is provided with at least one opening for the connection of a haulage duct, wherein the housing end side facing the bore hole is equipped with a lockable, particularly screwable, sealing flange ( 13 ) for the detachable connection with a bore hole lining ( 11 ). The sealing flange ( 13 ) is rotationally and sealingly mounted within the housing and carries projections, in particular an annular brim ( 15 ) which is overlapped by a stop ( 14 ) of the housing.

[0001] The invention relates to a device for sealing a bore hole anddischarging drill cuttings and stripped excavation material, including ahousing adapted to receive sealing elements and an opening capable ofbeing connected to the bore hole, wherein one side wall of the housingis provided with at least one opening for the connection of a haulageduct and the housing end side facing the bore hole is equipped with alockable, particularly screwable, sealing flange for the detachableconnection with a bore hole lining.

[0002] Devices of the initially defined kind are used, for instance, foroil drill cuttings with a device of this type being described, forinstance, in U.S. Pat. No. 4,529,210. The known devices are also denotedas blow-out preventors. However, when using same in the field ofoil-drilling technology, large free spaces are usually accessible abovethe bore hole such that the known blow-out preventors can be relativelylarge-structured, having to offer a tight rotary mounting for the drillrod assembly in the first place. As a rule, the structural prerequisitesof such preventors to be used in the field of oil-drilling technology,therefore, refer to the respective rotary mounting of a sealingly guidedstructural component which is itself designed as a coupling for theactuator of the drill rod assembly.

[0003] Devices of this type cannot be readily employed in criticaldrilling interventions by which a tunnel tube is made below ground andonly the clear height of the tunnel tube is subsequently available as afree space, because of their dimensions, on the one hand, and because oftheir limited flexibility as regards the use of different elements, onthe other hand. U.S. Pat. No. 5,380,127, for instance, describes amethod for excavating minerals by means of a jet boring system thatserves to work an ore deposit located below a lake. In that known methoda tunnel tube is driven, after which, upon introduction of appropriatebores and linings, an excavation tool in the form of a liquid jet headis moved into the guiding tubes or lining tubes for the jet boringprocess and minerals are stripped off and carried away by the aid ofhigh-pressure fluid and, in particular, high-pressure water. Suchdeposits, which call for extremely complex wallings, are to be found,for instance, in Canada, where the ore deposit would contain highconcentrations of uranium ores with an accordingly high degree ofcontamination by radiation. Especially high demands are made on thesafety and, in particular, sealing of such bores, and on top of thisthere is the risk in the event of natural lakes as are, for instance,found on top of such uranium ore deposits that water under high pressuremight penetrate such bores and guiding tubes with a failure of the sealbeing likely to cause considerable contamination.

[0004] The invention aims to provide a device of the initially definedkind for a method of the above type, by which the risk of contaminationof a tunnel tube can be excluded and the excavation of material iseffected by flushing the ore deposit with fluid under high pressure and,in particular, high-pressure water. For such a method, the device must,therefore, not only ensure the required tightness, but also offer theopportunity to sealingly introduce via said device structural componentshaving different diameters such as, in particular, drilling tools formaking bores, tubes for lining bore holes and finally fluid tubes forfeeding fluid to spraying heads or excavation heads, and to extend thesame below said device by attaching respectively short sections. Duringall those manipulations, the required tightness must, therefore, besafeguard at any time, which is not at all feasible by a single sealsuch that the arrangement of different seals and the rapid exchange ofsuch seals have to be rendered feasible. To solve this object, thedevice according to the invention, departing from a device of theinitially defined kind, essentially consists in that the sealing flangeis rotationally and sealingly mounted within the housing and carriesprojections, in particular an annular brim which is overlapped by a stopof the housing. Due to the fact that the sealing flange is rotationallyand sealingly mounted within the housing and carries projections, inparticular an annular brim which is overlapped by a stop of the housing,it is initially rendered feasible to use the blow-out preventor in asuspended manner for upwardly directed bores as will be required in thecontext of the method to be carried out by said device. With such asuspended arrangement, the housing itself must be sealingly connectablewith the bore-hole lining and will subsequently have to be appropriatelyoriented for the haulage of the material to be excavated. Bearing inmind the high pressure applied, flexible hoses cannot be readily used,and an accordingly pressure-proof tube system offering high tightnesswill have to be employed for haulage, thus involving substantialsafety-technological prerequisites not the least because of the risk ofcontamination in the event of untightness. The use of such rigid tighttubes, in turn, calls for the simple orientability of the deviceaccording to the invention relative to the tubes arranged within thetunnel and a relatively short structure of the same in order to enablethe respectively required extension pieces for the drill rod assembly,and the tube systems required for excavation, to be installed andsealingly guided through the blow-out preventor under the restrictedspace conditions prevailing in the interior of the tunnel. To this end,the blow-out preventor is arranged above the drilling station, whereaccordingly long-structured extension units can be attached on accountof the short mode of construction, whereupon, after driving of the bore,a suitable primary casing in the form of a bore-hole lining isintroduced, with its lowermost element being usually fixed within thebore hole upon appropriate solidification of the bore-hole wall, forinstance by pressing in concrete, after which the sealing flange can,for instance, be screwed with the final tube section. Such screwing, inturn, calls for the sealing flange to be sealingly mounting in arotational manner in the interior of the housing.

[0005] In order to further enhance safety, the configurationadvantageously is devised such that the sealing flange is surrounded bya sealing collar capable of being pressed against the edge of the borehole in the direction of the axis of the bore hole. Such a sealingcollar ensures perfect dust sealing relative to the tunnel liningalready in the drilling phase and is of particular advantage as anadditional safety element. The holding flange or sealing flange providessupport to the preventor suspended from the rock and even at theoccurrence of usual pressures of up to 70 bars acting on the seal withinthe preventor must intercept these pressures directly on the rockwithout material being diverted into the drilling station. The sealingcollar, which can be pressed against the edge of the bore hole in thedirection of the axis of the bore hole, advantageously is designed suchthat a pressure spring, in particularly a helical spring, is arrangedconcentric with the sealing collar surrounding the sealing flange,between the housing and a seal capable of being applied against the edgeof the bore hole, said application being adjustable by means of ahydraulic cylinder and said pressure spring, particularly helicalspring, ensuring an accordingly elastically resilient adaptation to theedge of the bore hole.

[0006] The device according to the invention advantageously is designedsuch that connections for flushing nozzles run into the interior of thehousing on the side wall of the housing, wherein at least one flushingnozzle in the interior of the housing is preferably directed onto a rodassembly or a conveyor tube intended to introduce excavation fluid to afluid-operated excavation head, and at least one flushing nozzle in theinterior of the housing is preferably oriented towards the haulage ductin the tangential direction. By such specifically oriented flushingnozzles, it is, for instance, feasible to reliably flush away materialadhering to the outer peripheries of parts of the drill rod assembly andtubing for the jet boring head, as the latter are being retracted, so asto safely maintain the sealing effect even during such axialdisplacements. By the flushing nozzles oriented substantially in thetangential direction, the haulage of the reclaimed material into theduct extending in the tunnel tube can be assisted and better divertedinto the discharge channel at the material delivery, what is ofparticular advantage especially with high portions of drill cuttings andstripped minerals being contained in the fluid flow.

[0007] In order to enable the rapid exchange of the respective sealingelements differently designed for different operating phases, theconfiguration advantageously is devised such that the fastening membersfor sealing elements on the housing end side facing away from the borehole are designed as bayonet catch members, wherein a rotatable bayonetring connected to a, particularly hydraulic, actuator is preferablyconnected with the housing. With the appropriate configuration of thelocking members the insertion and removal of sealing elements and/orsupporting parts of the sealing elements is feasible in a particularlysimple manner, especially by means of such a rotatable and hydraulicallyactuatable bayonet ring, wherein the configuration advantageously isdevised such that the sealing elements are designed to be frustoconical,or are fixed in a frustoconical carrier, and the inner wall regionsadjacent to the housing end side facing away from the bore hole areshaped in an accordingly hollow-conical manner. Such a configurationenables also high pressures to be reliably taken up, wherein it has tobe feasible to reliably absorb also extremely high pressures bearing inmind the suspended arrangement and the fact that, for instance, anatural lake can be located above an ore deposit. In this respect, theconfiguration advantageously is devised such that the sealing elementscapable of being fixed within the housing on its end side facing awayfrom the bore hole are designed as shaft seals or rod seals constructedto seal rotatable and/or axially displaceable drill rods and/or tubesintended to supply pressure medium to excavation tools.

[0008] In the following, the invention will be explained in more detailby way of an exemplary embodiment represented in the drawing, which isto be used under the special operating conditions of the initiallymentioned excavation method. In the drawing,

[0009]FIG. 1 is a partially sectioned schematic side view of the deviceaccording to the invention oriented towards a drilling station;

[0010]FIG. 2 is an illustration analogous to FIG. 1 upon insertion ofthe sealing flange;

[0011]FIG. 3 is an illustration analogous to FIGS. 1 and 2 uponintroduction of the tubing intended for jet boring;

[0012]FIG. 4 is an axial section through the device according to FIG. 3with an inserted high-pressure;

[0013]FIG. 5 is an illustration corresponding to that of FIG. 4 with asimple dust seal provided for the rod assembly;

[0014]FIG. 6 is a section according to FIG. 5, showing the respectiveconnections for the adjustment of the bayonet ring and the supply offlushing medium to the flushing nozzles, respectively; and

[0015]FIG. 7 is a top view on the closure ring used to fix the sealingelements.

[0016]FIG. 1 schematically elucidates the starting phase of theexcavation process extensively described in U.S. Pat. No. 5,380,127. Theblow-out preventor 2 is fixed on a drilling frame 1 with an elasticsealing collar 3 being pressed at the lining 5 of the tunnel by means ofa helical spring 4 and a drilling tool 6 being connected with thedrilling station 1. The drilling tool 6 is then advanced in the sense ofarrow 7, i.e., in the axial direction of the bore, whereby shortextension pieces are each arranged between the actuator and the drillbit in the drilling station 1. In this phase, the sealing collar 3safeguards perfect dust sealing relative to the tunnel lining, wherein amanipulator 8 is additionally apparent from the illustration accordingto FIG. 1, which serves to pivot the drilling tool and the extensionrods into the respective positions in the interior of the drillingstation. The drilling station 1 comprises hydraulic cylinder-pistonunits 9 to adjust the height position, whereby, during the extension ofa drill rod assembly, the respective drill rod assembly already drivenin is held in the region of the platform 10, for instance by clamps orclaws not illustrated, such that the respective extension piece can beinstalled therebelow.

[0017] In the illustration according to FIG. 2, the drill rod assemblyhas already been removed again and a bore hole lining 11 has beenintroduced into the bore hole. In the region adjacent to the tunnellining, the material is secured by concrete injections 12, andsubsequently a sealing flange 13 is screwed with the lower part of thebore hole lining 11. The blow-out preventor 2 is supported via inwardlyoriented flanges 14 on an accordingly outwardly oriented annular brim 15of the sealing flange 13 so as to be held suspended from the rock. Inaddition, the sealing collar 3 is again provided and pressed against thetunnel lining 5 by helical springs 4. In this phase, the housing of theblow-out preventor 2 is connected with the bore hole lining 11 in apressure-proof and tight manner, and the respective supply tubes for thehydraulic excavation process, i.e. jet boring, can be introduced via themanipulator 8. In this phase, a suitable high-pressure-proof seal 16 isfixed to the housing end side of the bore-hole preventor 2 facing awayfrom the bore hole, as is apparent particularly from FIG. 3, so as toenable the supply tubes 17 for pressure fluid to be sealingly insertedinto the bore hole tubing 11.

[0018] The structural details are more clearly visible in FIGS. 4 to 7.FIG. 4 clearly depicts the arrangement and support of the helical spring4 for the resilient application of the collar 3 at the tunnel lining. Tothis end, a front plate 18 is provided with an appropriate peripheralseal 19 on which one end of the spring 4 is supported, whose other endbears against an annular flange 20 firmly connected with the housing.The sealing flange 13, which carries an internal thread 21 to be screwedwith the bore hole lining 11, is sealingly mounted relative to thehousing 23 of the blow-out preventor by means of sealing rings 22, saidmounting enabling a rotation of the sealing flange 13 without any lossof its sealing effect, application sites for suitable tools beingschematically indicated at 24.

[0019] From FIG. 4, further connections 25 to flushing nozzles 26 areapparent, whose spraying axes intersect with the axis 27 of the borehole and tubes so as to enable material adhering to the outer shells ofthe tubes 17 to be flushed off towards the discharge opening 28 uponaxial displacement of the tubes 17.

[0020] To this discharge opening is connected the rigid tubing providedin the interior of the tunnel.

[0021] The high-pressure-proof sealing element 29 comprises a support 30with which elastomer sealing rings 31 are connected. To enhance thesealing effect, flushing channels 32 are provided, by which hollowspaces between sealing elements and the rod assembly can be kept underan overpressure so as to prevent drill cuttings from penetrating intothe same and enable optionally penetrating material to be flushed out.

[0022] By 33 is denoted a two-part ring which surrounds a mating annularflange 34 to which a bayonet ring 36 is fixed by screw bolts 35. Thesupport 30 of the sealing elements 31 comprises appropriate bayonetrecesses and projections, respectively, and itself is conically designedsuch that, by turning the bayonet ring 36, not only an axial securementof the sealing elements is ensured but also an axial pressure willsimultaneously be exerted on the sealing elements. Since the outerjacket of the support 30 of the sealing elements are designed to befrustoconical, as can be seen at 37, and the mating counter wall of thehousing 23 is designed to be conical, a highly firm and tight fixationof the sealing elements will be ensured.

[0023] In the illustration according to FIG. 5, only the simple dustseal is provided, the sealing elements 30, 31 thus being replaced with asimple-structured sealing element 38, which is fixed by the bayonet ring36. By this equipment drilling can be advanced, whereby the differentlyoriented spraying nozzles 26 are apparent from the illustrationaccording to FIG. 5. Laterally beside the sealing collar 3 is aspring-loaded tracer pin 39, which serves measuring and calibrationpurposes. Furthermore, the illustration according to FIG. 5 depicts ahydraulic cylinder-piston unit 40, which, in addition to the force ofthe spring 4, helps to keep the sealing element 19 and the collar 3 intheir sealing positions at the tunnel lining.

[0024] As is apparent from FIG. 6, tube flanges 41 are arrangedlaterally of the housing 23 of the blow-out preventor 2, which tubeflanges serve to feed flushing medium to the nozzles 26. FIG. 6,furthermore, depicts the mounting of the bayonet ring 33, 36 and a hingepoint 42 for a cylinder-piston unit that serves to rotate said bayonetring in order to release or fix said sealing elements. The details ofthe pivotability of the bayonet ring are visible from FIG. 7, whichillustrates the bayonet ring 36 from below. By means of the rod assembly43 of a hydraulic cylinder-piston unit, it is feasible to pivot thebayonet ring in the sense of double arrow 44 such that the respectivebayonet recesses 45 are either brought into alignment with therespective projections 46 of the respectively inserted sealing elementor, upon pivoting via wedge surfaces provided on the projections 46,exert an appropriate axial pressure force on the sealing elements. Inthe illustration according to FIG. 7, the support 30 of thehigh-pressure safety element is visible from below, wherein the baseplate of the blow-out preventor serving to fix the plate 10 to thedrilling station 1 is denoted by 47.

1. A device for sealing a bore hole and discharging drill cuttings andstripped excavation material, including a housing adapted to receivesealing elements and an opening capable of being connected to the borehole, wherein a side wall of the housing is provided with at least oneopening for the connection of a haulage duct and the housing end sidefacing the bore hole is equipped with a lockable, particularlyscrewable, sealing flange (13) for the detachable connection with a borehole lining (11), characterized in that the sealing flange (13) isrotationally and sealingly mounted within the housing and carriesprojections, in particular an annular brim (15) which is overlapped by astop of the housing.
 2. A device according to claim 1, characterized inthat the sealing flange (13) is surrounded by a sealing collar (3)capable of being pressed against the edge of the bore hole in thedirection of the axis (27) of the bore hole.
 3. A device according toclaim 1 or 2, characterized in that connections (25) for flushingnozzles (26) run into the interior of the housing on the side wall ofthe housing.
 4. A device according to claim 3, characterized in that atleast one flushing nozzle (25) in the interior of the housing isdirected onto a rod assembly or a conveyor tube intended to introduceexcavation fluid to a fluid-operated excavation head.
 5. A deviceaccording to claim 3 or 4, characterized in that at least one flushingnozzle (25) in the interior of the housing is oriented towards thehaulage duct (17) in the tangential direction.
 6. A device according toany one of claims 1 to 5, characterized in that fastening membersdesigned as bayonet catch members (36) are provided on the housing endside facing away from the bore hole for the sealing elements (31).
 7. Adevice according to any one of claims 1 to 6, characterized in that arotatable bayonet ring (36) connected to a, particularly hydraulic,actuator (43) is connected with the housing.
 8. A device according toany one of claims 1 to 7, characterized in that the sealing elements(29, 31) capable of being fixed within the housing on its end sidefacing away from the bore hole are designed as shaft seals or rod sealsconstructed to seal rotatable and/or axially displaceable drill rodsand/or tubes (17) for supplying pressure medium to excavation tools. 9.A device according to claim 8, characterized in that the sealingelements (16, 29, 31) are designed to be frustoconical, or are fixed ina frustoconical carrier, and the inner-wall regions adjacent to thehousing end side facing away from the bore hole are shaped in anaccordingly hollow-conical manner.
 10. A device according to any one ofclaims 1 to 9, characterized in that a pressure spring, in particular ahelical spring (4), is arranged concentric with the sealing collar (3)surrounding the sealing flange (13), between the housing and a sealcapable of being applied against the edge of the bore hole.